(19)
(11) EP 0 741 159 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
01.10.1997 Bulletin 1997/40

(43) Date of publication A2:
06.11.1996 Bulletin 1996/45

(21) Application number: 96303109.1

(22) Date of filing: 02.05.1996
(51) International Patent Classification (IPC)6C08G 77/12, C08G 77/08, C08G 77/38, C07F 7/08
(84) Designated Contracting States:
DE FR GB IT

(30) Priority: 03.05.1995 US 433181

(71) Applicant: DOW CORNING CORPORATION
Midland, Michigan 48686-0994 (US)

(72) Inventors:
  • Biggs, Timothy Nolen
    Midland, Michigan 48640 (US)
  • Legrow, Gary Edward
    Midland, Michigan 48642 (US)

(74) Representative: Lewin, John Harvey 
Elkington and Fife, Prospect House, 8 Pembroke Road
Sevenoaks, Kent TN13 1XR
Sevenoaks, Kent TN13 1XR (GB)

   


(54) Methods of making polysiloxanes


(57) Linear or straight-chain trimethylsiloxy endcapped methylhydrogen polysiloxanes are made by contacting hexamethyldisiloxane with a highly pure methylhydrogen cyclic siloxane, in the presence of anhydrous trifluoromethane sulfonic acid catalyst at room temperature. Trimethylsiloxy endcapped alkylmethyl siloxanes are made by reacting the linear or straight-chain trimethylsiloxy endcapped methylhydrogen polysiloxanes with an alpha-olefin, in the presence of a platinum catalyst. Alkylmethyl cyclic siloxanes containing zero parts per million residual ≡SiH, are made by reacting anhydrous alpha-olefins and a highly pure methylhydrogen cyclic siloxane, in the presence of dried platinum catalyst supported on carbon particles.





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